Hazardous gas detection technology is one of the necessary guarantees of safety in many industries such as petrochemical enterprises, and plays an important role in industrial production. To make up for the shortage of single-frame gas leak detection algorithm which based on infrared imaging technology and improve the detection accuracy, a method of optical flow enhanced infrared imaging gas leak detection was proposed in this paper. The motion features in the video are extracted with the optical flow network in the first step. Then the motion features are fused with the original image to generate an optical flow enhanced gas leak image to be sent to the YOLO network for detection. Finally, whether there is a leakage in the video was determined and its location was obtained. After a comparison with the data before enhancement, the method keeps the recall rate in an acceptable range while the false alarm rate is reduced from 17. 87% to 0. 60%, and precision is improved from 77. 21% to 99. 99%. The detection speed is about 13 fps, which satisfies the needs of real-time detection.